Yes, both LiveAgent and Contact At Once offer a Free Trial.
LiveAgent is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
Contact At Once is designed for Medium Business and Small Business.
Pricing for LiveAgent Starts at $15/User/Month whereas for Contact At Once Starts at $1,100/Month.
Some top alternatives to LiveAgent includes Zendesk Support, Zoho Desk, Tidio Helpdesk, Freshservice, ManageEngine ServiceDesk Plus, Freshdesk, ClickDesk, HelpDesk, SysAid, Jitbit Helpdesk, Desky, Help Scout, LabiDesk, LiveChat, Zendesk Chat, LiveHelpNow and Little SaaS Communication.
Some top alternatives to Contact At Once includes ZoomInfo Chat, LiveAgent, LiveChat, Crisp, LiveEngage, MyLiveChat, Smartchat, raychat, LinkedChat, ChatFlow247 and Let's Connect.